Generation and characterization of inhibitory nanobodies towards thrombin activatable fibrinolysis inhibitor

作者：Buelens K; Hassanzadeh Ghassabeh G; Muyldermans S; Gils A; Declerck P J^*

来源：Journal of Thrombosis and Haemostasis, 2010, 8(6): 1302-1312.

DOI：10.1111/j.1538-7836.2010.03816.x

• fibrinolysis
• inhibition
• nanobodies
• TAFI
• profibrinolytic

Background and objective: As activated thrombin-activatable fibrinolysis inhibitor (TAFIa) is a potent antifibrinolytic enzyme, the development of TAFI inhibitors is a new promising approach in the development of profibrinolytic drugs. We, therefore, aimed to generate nanobodies, camelid-derived single-domain antibodies towards TAFI. Methods and results: This study reports the generation and characterization of a panel of 22 inhibitory nanobodies. This panel represents a wide diversity in mechanisms for interference with the functional properties of TAFI as the nanobodies interfere with various modes of TAFI activation, TAFIa activity and/or TAFI zymogen activity. Nanobodies inhibiting TAFIa activity and thrombin/thrombomodulin-mediated TAFI activation revealed pro. brinolytic properties in a clot lysis experiment with exogenously added thrombomodulin (TM), whereas nanobodies inhibiting plasmin-mediated TAFI activation only revealed pro. brinolytic properties in a clot lysis experiment without TM. The results of in vitro clot lysis experiments provided evidence that inhibitory nanobodies penetrate the clot better compared with inhibitory monoclonal antibodies. Conclusions: These data suggest that the generated nanobodies are potent TAFI inhibitors and are a step forward in the development of a pro. brinolytic drug. They might also be an excellent tool to unravel the role of the physiological activators of TAFI in various pathophysiological processes.

• 出版日期2010-6